大断面注浆硐室围岩稳定性分析及控制技术

Stability analysis and controlling technique for surrounding rock of grouting chamber with large cross section

为解决大断面注浆硐室围岩稳定性控制难题,采用FLAC3D软件对硐室围岩变形破坏特征进行了模拟分析。数值模拟结果表明硐室围岩变形控制的关键部位为硐室顶底板的边角部位和硐壁中部。硐室开挖采用"溜井出渣、分层开挖、及时支护"的思路,尽量减小开挖扰动对围岩的破坏。硐顶与硐壁支护方法为"锚网索喷"联合支护,临时"初喷"支护及时封闭围岩,二次"锚网索喷"支护充分调动了围岩的自承载能力。硐底部分采用锚索和钢筋混凝土衬砌支护,避免硐底边角部位产生剪切破坏。监测结果表明支护结构能够较好地满足了硐室长期稳定性和防渗要求。

For the purpose to solving the difficulties in controlling the stability of surrounding rock of the large cross section chamber,FLAC 3D software is used to simulate the failure characteristics of the surrounding rock for the chamber.Results of the simulation indicate that key positions for controlling the surrounding rock deformation are the corners in roof and floor of the chamber and the middle in the chamber wall.The principle of the excavation includes using ore pass to putting down the gangue,excavation from top to bottom in slice,and immediate supporting technical,which aims to reduce the failure caused by excavation disturbance.Combined support scheme of“anchor bolt+anchor cable+steel mesh+sprayed concrete”is proposed to support the roof and wall of the chamber.The first-time shotcrete sealing the surrounding rock timely,while the subsequent supporting technique of“anchor bolt+anchor cable+steel mesh+sprayed concrete”could improve the bearing capacity of the surrounding rock.Reinforced concrete and anchor cable is used in the bottom supporting of the chamber in order to avoiding shear failure in the corner in the floor.Monitoring results indicate the supporting structure greatly meet the long-term requirements of stability and seepage-proofing for surrounding rock of the chamber.